Single local oscillator in a multi-band frequency division duplex transceiver

ABSTRACT

Embodiments of the present disclosure relate to multi-band FDD transceivers. An example transceiver includes a LO, configured to generate a LO signal to be shared between a receiver and a transmitter of the transceiver. Both the receiver and the transmitter use quadrature signal processing and are configured to multi-band operation. Sharing a single LO to perform frequency conversion of different frequency bands of received and transmitted signals advantageously allows reducing the number of LOs used in a multi-band FDD transceiver.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority from PCT ApplicationNo. PCT/CN2019/072222 filed 17 Jan. 2019, entitled “SINGLE LOCALOSCILLATOR IN A MULTI-BAND FREQUENCY DIVISION DUPLEX TRANSCEIVER”,incorporated herein by reference in its entirety.

TECHNICAL FIELD OF THE DISCLOSURE

The present disclosure generally relates to radio frequency (RF) systemsand, more particularly, to frequency division duplex (FDD) systems andcomponents.

BACKGROUND

Radio systems are systems that transmit and receive signals in the formof electromagnetic waves in the RF range of approximately 3 kiloHertz(kHz) to 300 gigaHertz (GHz). Radio systems are commonly used forwireless communications, with cellular technology being a prominentexample.

Cellular technology is constantly evolving to support growing widespreadwireless technology usage. Recently, popular wireless standardizedtechnology has progressed from Global System for Mobile Communication(GSM) to Wideband Code Division Multiple Access (WCDMA) to Long TermEvolution (LTE). Cellular systems are deployed in many frequency bandsthat are defined by a combination of standardization organizations suchas the 3d Generation Partnership Project (3GPP) and government-sponsoredagencies such as the Federal Communications Commission (FCC). There areboth FDD and time division duplex (TDD) variants of frequencyallocations that are used in commercial cellular networks. In FDDsystems, the uplink and downlink use separate frequency bands at thesame time while, in TDD systems, the uplink and downlink use the samefrequencies at different times.

Base station transceivers capable of receiving multiple frequency bandswith a single signal path (i.e., multi-band transceivers) have nowbecome commonplace. These multi-band transceivers have the potential ofadvantageously lower cost and smaller size as compared to systemsutilizing separate transceivers dedicated to each band.

As the foregoing illustrates, with all of the challenges of constantlyevolving demands of wireless technology, designing an optimal RFtransceiver, i.e., an RF device that can both send and receive RFsignals having information encoded therein, is not trivial. Onechallenge with FDD transceivers supporting multi-band operation is thenumber of local oscillators (LO) used to downconvert received signalsfrom RF to baseband (if direct conversion is used) or to an IF(intermediate frequency; if heterodyne conversion is used) and to,similarly upconvert signals to be transmitted. The number of LOs thathave to be included in a system is important because LOs generally donot scale well in terms of power dissipation and chip area. Furthermore,as more and more components are integrated in a single integratedcircuit (IC), generation and distribution of a LO signal is a majorcontributor to spurious issues to highly integrated RF ICs.

BRIEF DESCRIPTION OF THE DRAWINGS

To provide a more complete understanding of the present disclosure andfeatures and advantages thereof, reference is made to the followingdescription, taken in conjunction with the accompanying figures, whereinlike reference numerals represent like parts, in which:

FIG. 1 illustrates an example wireless communication system, accordingto some embodiments of the present disclosure;

FIG. 2 provides a block diagram illustrating an example RF transceiver,according to some embodiments of the present disclosure;

FIG. 3 provides an illustration of using a single LO for receiving andtransmitting signals in multiple receive (RX) and transmit (TX) bands,according to some embodiments of the present disclosure;

FIG. 4 provides an illustration of using a single LO for receiving andtransmitting signals in multiple RX and TX bands where the LO signal iswithin one of the RX bands, according to some embodiments of the presentdisclosure;

FIG. 5 provides an illustration of using a single LO for receiving andtransmitting signals in multiple RX and TX bands where the LO signal iswithin one of the TX bands, according to some embodiments of the presentdisclosure;

FIG. 6 provides an illustration of using two LOs for receiving andtransmitting signals in multiple RX and TX bands, according to someembodiments of the present disclosure;

FIG. 7 provides a block diagram illustrating an example RF transceiverusing two LOs for receiving and transmitting signals in multiple RX andTX bands, according to some embodiments of the present disclosure; and

FIG. 8 provides a block diagram illustrating an example data processingsystem that may be configured to implement at least portions of themethod shown in FIG. 8, according to some embodiments of the presentdisclosure.

DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE DISCLOSURE

Overview

The systems, methods and devices of this disclosure each have severalinnovative aspects, no single one of which is solely responsible for theall of the desirable attributes disclosed herein. Details of one or moreimplementations of the subject matter described in this specificationare set forth in the description below and the accompanying drawings.

Embodiments of the present disclosure relate to multi-band FDDtransceivers. In one aspect, a multi-band FDD transceiver systemincludes a LO, configured to provide a LO signal to be shared between areceiver and a transmitter of the transceiver system, i.e., to be sharedbetween an RX path and a TX path of the transceiver. Both the receiverand the transmitter use quadrature signal processing and are configuredto multi-band operation. The RX path includes a RX path mixer (alsocommonly known as a “downconverter”), configured to mix the LO signalwith an RX signal to generate a mixed RX signal, where the RX signalincludes a first RX signal component in a first band of RX frequenciesand a second RX signal component in a second band of RX frequencies, thesecond band of RX frequencies being non-overlapping and non-continuouswith the first band of RX frequencies. The TX path includes a TX pathmixer (also commonly known as an “upconverter”), configured to mix theLO signal with a TX signal to generate a mixed TX signal, where themixed TX signal includes a first TX signal component in a first band ofTX frequencies and a second TX signal component in a second band of TXfrequencies, the second band of TX frequencies being non-overlapping andnon-continuous with each one of the first band of TX frequencies, thefirst band of RX frequencies, and the second band of RX frequencies.Sharing a single LO to perform frequency conversion of differentfrequency bands of RX and TX signals advantageously allows reducing thenumber of LOs used in an FDD transceiver.

As will be appreciated by one skilled in the art, aspects of the presentdisclosure, in particular aspects of sharing a single LO for frequencyconversion of various signal components in RX and TX paths of amulti-band FDD transceiver as described herein, may be embodied invarious manners—e.g. as a method, a system, a computer program product,or a computer-readable storage medium. Accordingly, aspects of thepresent disclosure may take the form of an entirely hardware embodiment,an entirely software embodiment (including firmware, resident software,micro-code, etc.) or an embodiment combining software and hardwareaspects that may all generally be referred to herein as a “circuit,”“module” or “system.” Functions described in this disclosure may beimplemented as an algorithm executed by one or more hardware processingunits, e.g. one or more microprocessors, of one or more computers. Invarious embodiments, different steps and portions of the steps of anymethods described herein may be performed by different processing units.Furthermore, aspects of the present disclosure may take the form of acomputer program product embodied in one or more computer-readablemedium(s), preferably non-transitory, having computer-readable programcode embodied, e.g., stored, thereon. In various embodiments, such acomputer program may, for example, be downloaded (updated) to theexisting devices and systems (e.g. to the existing RF transceiversand/or their controllers, etc.) or be stored upon manufacturing of thesedevices and systems.

The following detailed description presents various descriptions ofspecific certain embodiments. However, the innovations described hereincan be embodied in a multitude of different ways, for example, asdefined and covered by the claims or select examples. In the followingdescription, reference is made to the drawings where like referencenumerals can indicate identical or functionally similar elements. Itwill be understood that elements illustrated in the drawings are notnecessarily drawn to scale. Moreover, it will be understood that certainembodiments can include more elements than illustrated in a drawingand/or a subset of the elements illustrated in a drawing. Further, someembodiments can incorporate any suitable combination of features fromtwo or more drawings.

The description may use the phrases “in an embodiment” or “inembodiments,” which may each refer to one or more of the same ordifferent embodiments. Unless otherwise specified, the use of theordinal adjectives “first,” “second,” and “third,” etc., to describe acommon object, merely indicate that different instances of like objectsare being referred to, and are not intended to imply that the objects sodescribed must be in a given sequence, either temporally, spatially, inranking or in any other manner. Various aspects of the illustrativeembodiments are described using terms commonly employed by those skilledin the art to convey the substance of their work to others skilled inthe art. The terms “substantially,” “approximately,” “about,” etc., maybe used to generally refer to being within +/−20% of a target valuebased on the context of a particular value as described herein or asknown in the art. For the purposes of the present disclosure, the phrase“A and/or B” or notation “A/B” means (A), (B), or (A and B). For thepurposes of the present disclosure, the phrase “A, B, and/or C” means(A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C). Theterm “between,” when used with reference to measurement ranges, isinclusive of the ends of the measurement ranges. As used herein, thenotation “A/B/C” means (A, B, and/or C).

Example Wireless Communication System

FIG. 1 illustrates a wireless communication system 100, according tosome embodiments of the present disclosure. The wireless communicationsystem 100 may include a base station 110 and a plurality of mobilestations, examples of which are shown in FIG. 1 as a first mobilestation 120, a second mobile station 130, and a third mobile station140. The base station 110 may be coupled to backend network (not shown)of the wireless communication system and may provide communicationbetween the mobile stations 120-140 and the backend network. In variousembodiments, the wireless communication system 100 may include aplurality of base stations similar to the base station 110, which basestations may, e.g., be arranged in cells, where only one base station110 is shown in FIG. 1 for simplicity and illustration purposes.

The wireless communication system 100 may support multiple standards andmultiple band communication. For example, the wireless communicationsystem may support LTE, WCDMA, and GSM standard communication. Each ofthe mobile stations 120-140 may support any one or more of thesestandards. However, the use of these listed standards is merelyexemplary and other standards also may be supported by different partsof the wireless communication system 100. In addition to multiplestandard capabilities, the wireless communication system 100 may alsosupport multiple communication bands. For example, the wirelesscommunication system 100 may support DCS/PCS bands and GSM850/GSM900bands of GSM.

The multiple standard, multiple band signals that are transmitted andreceived in the base station 110 of the wireless communication system100 may be classified into two groups. A first group may refer to thesignals for which direct conversion may be applicable, and a secondgroup may refer to the signals for which direct conversion may notapplicable. In the FIG. 1 example described above, LTE and WCDMA mayfall in the first group for which direct conversion is applicable in abase station, and GSM may fall in the second group for which directconversion is not applicable in a base station. Although directconversion provides benefits such as low system cost, improvedout-of-band performance, low power dissipation, and low component cost,some standard performance requirements are not feasible with directconversion. For example, since a received RF signal is mixed directly tobase band in direct conversion, harmonic distortions and images may fallin band. And while some standard performance requirements may besufficiently low for direct conversion applications such as LTE andWCDMA that require approximately 70 dB image and harmonic rejection,other systems may require higher performance not feasible with directconversion such as MC-GSM that requires 90 dB rejection.

The base station 110 may support wireless communication with mobilestations 120-140 of various standard technologies as well as in multiplebands. The base station 110 may transmit signals to the mobile stations120-140 in downlink signals and receive signals from the mobile stations120-140 in uplink signals. For example, the base station 110 may receiveLTE compliant signals from the first mobile station 120, WCDMA signalsfrom the second mobile station 130, and GSM signals from the thirdmobile station 140. The base station 110 may convert the receivedsignals to baseband signals, possibly by first converting them to IFsignals, or low-IF signals, to demodulate and extract information fromtherein.

Example Multi-Band FDD Transceiver

FIG. 2 is a simplified block diagram of an RF transceiver 200, accordingto some embodiments of the present disclosure. For example, thetransceiver 200 may be provided in the base station 110 of FIG. 1. Inanother example, the transceiver 200 may be provided in any of themobile stations 120-140 of FIG. 1. The transceiver 200 may support bothaforementioned groups of signals—signals for which direct conversion isapplicable (e.g., LTE, WCDMA) and signals for which direct conversion isnot applicable (e.g., MC-GSM). Accordingly, the transceiver 200 may beset to provide direct conversion for the first group of signals or toprovide low-IF conversion for the second group of signals (and firstgroup) using common circuit components as a single monolithictransceiver.

As shown in FIG. 2, the transceiver 200 may include an antenna 202.Because the transceiver 200 is an FDD transceiver, the antenna 202 maybe configured for concurrent reception and transmission of communicationsignals in separate, i.e., non-overlapping and non-continuous, bands offrequencies, e.g. in bands having a separation of, for example, severalmegahertz (MHz) from one another. Because the transceiver 200 is amulti-band transceiver, the antenna 202 is configured for concurrentreception of signals having multiple components in separate frequencybands, i.e. a given signal received by the antenna 202 may be seen as awideband signal that may include a plurality of RX signal components indifferent bands. Similarly, the antenna 202 is configured for concurrenttransmission of signals having multiple components in separate frequencybands, i.e. a given signal transmitted by the antenna 202 may be seen asa wideband signal that may include a plurality of TX signal componentsin different bands. In various embodiments, the antenna 202 may be asingle wideband antenna or a plurality of band-specific antennas (i.e.,a plurality of antennas each configured to receive and transmit signalsin a specific band of frequencies).

As also shown in FIG. 2, an output of the antenna 202 may be coupled tothe input of a multi-band FDD duplexer 204. The multi-band FDD duplexer204 is an electromagnetic component configured for filtering multiplesignals to allow for bidirectional communication over a single pathbetween the duplexer 204 and the antenna 202. To that end, the duplexer204 may be configured for providing RX signals to a receiver of themulti-band FDD transceiver 200, the receiver illustrated in FIG. 2 witha RX path 210, and for receiving TX signals from a transmitter of themulti-band FDD transceiver 200, the transmitter illustrated in FIG. 2with a TX path 230.

The multi-band nature of the receiver of the FDD transceiver 200, i.e.,the fact that each of the RX signals may have RX signal components inseparate frequency bands, is schematically illustrated in FIG. 2 withmultiple RX signal peaks 206 shown in the RX path 210. Similarly, themulti-band nature of the transmitter of the FDD receiver 200, i.e., thefact that each of the TX signals may have TX signal components inseparate frequency bands, is schematically illustrated in FIG. 2 withmultiple TX signal peaks 208. Thus, each of the RX path 210 and the TXpath 230 is configured to operate in multiple bands simultaneously. Forexample, 3GPP FDD bands currently have bandwidths ranging from 10 MHz tomore than 75 MHz, and the transceiver 200 may be configured to supportany and all of these bands that fall within the transceiver bandwidth,TR×BW. In various embodiments, TR×BW may range from less than 100 MHz tomore than 1 GHz.

The RX path 210 provides an example of one receiver circuit that may beincluded in the transceiver 200, and the TX path 230 provides an exampleof one transmitter circuit that may be included in the transceiver 200.In other embodiments, multiple receiver circuits and/or multipletransmitter circuits may be included in the transceiver 200, with onlyone of each shown in FIG. 2 for simplicity and illustration purposes.For example, in some embodiments, the transceiver 200 may include anynumber between 2 and 64 of the RX paths 210 and any number between 2 and64 of the TX paths 230.

FIG. 2 further illustrates a LO 250 (which may also be referred to as a“LO quadrature generator” 250), configured to provide LO signals to boththe RX path 210 and the TX path 230. Namely, as described in greaterdetail below, the LO 250 is configured to provide an LO signal to thequadrature mixer 220 in the RX path 210, and to provide the same LOsignal to the quadrature mixer 240 in the TX path 230. Assuming that thebandwidth of the transceiver 200 is denoted as TR×BW and the frequencyof the oscillation signal generated by the LO 250 is denoted as LO, onthe RX path 210, a multi-band signal received by the antenna 202 andincluding signal components in a range of RF frequencies from LO-TR×BW/2to LO+TR×BW/2 is downconverted (using the LO signal and the RXquadrature mixer 220, as described below) to a complex signal ranging,in frequencies, from −TR×BW/2 to TR×BW/2, to be converted to digitalform. On the other hand, on the TX path 230, a multi-band signal ofbandwidth TR×BW, as received by the TX quadrature mixer 240, isupconverted (using the LO signal and the TX quadrature mixer 240, asdescribed below) to a range of RF frequencies from LO-TR×BW/2 toLO+TR×BW/2, to be transmitted by the antenna 202.

In some embodiments, the LO 250 may include a phase lock loop (PLL) andan oscillator. The LO 250 may generate LO signals at differentfrequencies. The different frequencies may be selected based, e.g., onthe current signal properties for multi-band RX and TX signals andfrequency bands included therein.

At least some parts of the functionality of the LO 250, e.g., thefrequency of the oscillation signal generated by the LO 250, may becontrolled by a controller 270 which may either be included within thetransceiver 200, or be external, but communicatively coupled, to thetransceiver 200. In some embodiments, the controller 270 may furthercontrol other aspects, components, and features of the transceiver 200,described herein. Exemplary data processing system which may be used toimplement the controller 270 is shown in FIG. 8.

Turning to the details of the RX path 210, as shown in FIG. 2, the RXpath 210 may include a low-noise amplifier (LNA) 212, a harmonic orband-pass filter 214, a transformer 216, a variable attenuator 218, apair of RX path mixers 220-1 and 220-2, a pair of filters 222-1 and222-2, and a pair of analog-to-digital converters (ADCs) 224-1 and224-2. Two or more components of the RX path 210 may be provided on amonolithically IC.

An input of the LNA 212 may be coupled to an antenna port (not shown) ofthe antenna 202 (via the duplexer 204), which, in turn, may be coupledto the antenna 202. The antenna 202 may receive RF signals in differentbands, and the LNA 212 may amplify the received RF signals. The LNA 212may be coupled to the harmonic or band-pass filter 214 that may filterreceived RF signals that have been amplified by the LNA 212.

The harmonic or band-pass filter 214 may be coupled to the transformer216. In some embodiments, the transformer 216 may be provided as a balunmatching transformer. The transformer 216 may convert the receivedsignal into a balanced signal (i.e., two out-of-phase signals), thusproviding a conversion from a single-ended transmission line to adifferential transmission line. The balanced side of the transformer 216may be coupled to the input variable attenuator 218.

The input variable attenuator 218 may be coupled to the pair of RX pathmixers 220-1 and 220-2 (which, together, may be referred to as an “RXquadrature mixer 220” or a “downconverter 200”). Each of the RX pathmixers 220-1 and 220-2 may include two inputs and one output. A firstinput may receive the RX signals, which may be current signals, fromboth balanced nodes of the input variable attenuator 218. A second inputof each of the RX path mixers 220-1 and 220-2 may be coupled the outputof the LO 250 so that each of the RX path mixers 220-1 and 220-2 canreceive the LO signal generated by the LO 250 and use it fordownconverting.

The RX path 210 of the transceiver 200 may receive and downconvertsignals employing different downconversion techniques—directdownconversion and low-IF downconversion, e.g. based the mode selectionas described in co-pending US 2016/0100455A1. To that end, for firstgrouped signals, the RX path mixers 220-1 and 220-2 may downconvert thereceived RF signals directly to baseband signals, which may besubstantially at or near 0 Hz. On the other hand, for second groupedsignals, the RX path mixers 220-1 and 220-2 may downconvert the RFsignals to low-IF signals. For example, the low-IF signals may besubstantially at or near about 10 MHz. The first RX path mixer 220-1 maygenerate an in-phase (I) downconverted RX signal by mixing the RX signalreceived from the transformer 216 and an in-phase component of the LOsignal (i.e., cos(LO), labeled in FIG. 2 at the second input to thefirst RX path mixer 220-1). The output of the first RX path mixer 220-1may be provided to an I-signal path. The second RX path mixer 220-2 maygenerate a quadrature phase (Q) downconverted signal by mixing the RXsignal received from the transformer 216 and a quadrature component ofthe LO signal (i.e., sin(LO), labeled in FIG. 2 at the second input tothe second RX path mixer 220-2, which is a component that is offset inphase from the in-phase component of the LO signal by 90 degrees). Theoutput of the second RX path mixer 220-2 may be provided to a Q-signalpath, which may be substantially 90 degrees out of phase with theI-signal path.

The outputs of the RX path mixers 220-1 and 220-2 may, optionally, becoupled to respective filters 222-1 and 222-2, which may be low-passfilters, configured to filter out, from the mixed RX signals output bythe mixers 220-1 and 220-2, the signal components above a certainfrequency. The mixed RX signals from the RX quadrature mixer 220 maythen be provided to a quadrature ADC 224 that, similar to the RXquadrature mixer 220, includes two ADCs 224-1 and 224-2, configured todigitize the downconverted RX path signals. The ADCs 224-1 and 224-2 mayaccommodate both the downconverted baseband signals belonging to thefirst group and, alternatively, the downconverted IF signals belongingto the second group. In some embodiments, the controller 270 may adjustthe bandwidth of ADCs 224-1 and 224-2 based on the mode select.

The outputs of the RX path ADCs 224-1 and 224-2 may be provided to adigital block 260, configured to perform various functions related todigital processing of the RX signals so that information encoded in theRX signals can be extracted. Such functions may include decimation(downsampling), quadrature error correction, digital downconversion, DCoffset cancellation, automatic gain control, etc. In some embodiments,the digital block 260 may include a Hilbert filter (not shown),configured to receive the digital mixed RX signal in the Q-signal path(i.e., digitized output generated by the ADC 224-2), shift the Q-signalby 90 degrees and perform a Fourier Transform. The output of such aHilbert filter may then be summed with the digital output in theI-signal path of the RX path 210 (i.e., output digitized by the ADC224-1) by a summer (not shown), which may output an analytic basebandsignal from which information may be extracted. The summer output may becoupled to a baseband processor, which may extract the information. Fordirect conversion operations, such a Hilbert filer may be bypassed.

Turning now to the TX path 230, as shown in FIG. 2, the TX path 230 mayinclude a power amplifier (PA) 232, a transformer 236, a TX pathquadrature mixer (or “upconverter”) 240 that includes a pair of TX pathmixers 240-1 and 240-2, a pair of filters 242-1 and 242-2, and a pair ofdigital-to-analog converters (DACs) 244-1 and 244-2. Two or morecomponents of the TX path 230 may be provided on a monolithically IC,which may either be the same or a different circuit from the one thatmay include two or more components of the RX path 210.

The quadrature digital signal to be transmitted (TX signal) may beprovided, from the digital block 260, to the DACs 244-1 and 244-2,configured to convert, respectively, digital I- and Q-path TX signalcomponents to analog form. Optionally, the outputs of the DACs 244-1 and244-2 may be coupled to respective filters 242-1 and 242-2, which may beband-pass filters, configured to filter out, from the analog TX signalsoutput by the DACs 244-1 and 244-2, the signal components outside of thedesired band. The digital TX signals may then be provided to the TX pathquadrature mixer 240 that includes a pair of TX path mixers 240-1 and240-2.

Similar to the mixers 220-1 and 220-2 included in the RX path 210, eachof the TX path mixers 240-1 and 240-2 may include two inputs and oneoutput. A first input may receive the TX signal components, converted tothe analog form by the respective DAC 244, which are to be upconvertedto generate RF signals to be transmitted. The first TX path mixer 240-1may generate an in-phase (I) upconverted signal by mixing the TX signalcomponent converted to analog form by the DAC 244-1 with the in-phasecomponent of the LO signal (i.e., cos(LO), labeled in FIG. 2 at thesecond input to the first TX path mixer 240-1). The second TX path mixer240-2 may generate a quadrature phase (Q) upconverted signal by mixingthe TX signal component converted to analog form by the DAC 244-2 withthe quadrature component of the LO signal (i.e., sin(LO), labeled inFIG. 2 at the second input to the second TX path mixer 240-2, which, asdescribed above, is a component that is offset in phase from thein-phase component of the LO signal by 90 degrees). The output of thesecond TX path mixer 240-2 is added to the output of the first TX pathmixer 240-1 to create a real RF signal. A second input of each of the TXpath TX path mixers 240-1 and 240-2 may be coupled the LO 250, which isthe same LO as the one providing oscillation signals to the RX path 210,as described in greater detail below.

The outputs of the TX path mixers 240-1 and 240-2 may be coupled to thetransformer 236, which may be provided as a balun matching transformer,configured to convert the differential signal to a single-ended signal.

An output of the transformer 236 may be coupled to an input of the PA232, and the output of the PA 232 may be coupled to an antenna port (notshown) of the antenna 202 (via the duplexer 204), and, thereby coupledto the antenna 202. The PA 232 may amplify the mixed TX signals to betransmitted by the transceiver 200, and the antenna 202 may transmit theamplified TX signals.

FIG. 2 further illustrates a clock generator 252, which may, e.g.,include a suitable PLL, configured to receive a reference clock signaland use it to generate a different clock signal which may then be usedfor timing the operation of the ADCs 224, DACs 244, and/or which mayalso be used by the LO 250 to generate the LO signal to be used by theRX quadrature mixer 220 and the TX quadrature mixer 240. In otherembodiments, the LO 250 may receive a different reference clock signal(not shown), i.e., not the one used for clocking the ADCs 224 and DACs244, for generating the LO signal from.

The transceiver 200 provides a simplified version and, in furtherembodiments, other components not specifically shown in FIG. 2 may beincluded. For example, the RX path 210 may include a pair ofcurrent-to-voltage amplifiers between the RX path mixers 220-1, 220-2and respective ADCs 224-1, 224-2, which amplifiers may amplify andconvert the downconverted signals to voltage signals and which,optionally, may have bandwidth that is tunable by the controller 270 toaccommodate both the downconverted baseband signals belonging to thefirst group or, alternatively, the downconverted IF signals belonging tothe second group.

Furthermore, in various embodiments, the digital block 260 may includeseparate digital blocks for processing received signals and signals tobe transmitted.

Sharing a Single LO in a Multi-Band FDD Setting

Embodiments of the present disclosure are based on recognition that, ina multi-band transceiver setting, signal components of separatefrequency bands may be viewed as signal components of a given multi-bandsignal having wide bandwidth, the term “wide” used to reflect the factthat the bandwidth of a combination of signal components of separatefrequency bands is wider than a bandwidth of each of the signalcomponent. Embodiments of the present disclosure are further based onrecognition that a single LO signal may be used to downconvert multiplesignal components of a multi-band RX signal and to upconvert multiplesignal components of a multi-band TX signal.

Various example scenarios of how a frequency of the LO signal may beselected with respect to the frequencies of the different RX and TXbands with which the transceiver 200 may operate are illustrated inFIGS. 3-6. Each of these figures illustrates the frequency placement ofthe LO signal as generated by the LO 250, and separate frequency bandsof the multi-band RX and TX signals as may be, respectively, receivedand transmitted by the antenna 202. Thus, the x-axis of each of FIGS.3-6 is used to show frequency values, measured in MHz, while the y-axisof each of FIGS. 3-6 is a somewhat arbitrary illustration of theamplitude of the signals, showing that, in general, the downlinkoperating bands (i.e., TX signals) are usually larger in amplitude thanthe uplink operating bands (i.e., the RX signals), and both are largerthan the amplitude of the LO signal generated by the LO 250.

What may be considered to be a general scenario is illustrated in agraph 300 shown in FIG. 3, illustrating that, in general, the frequencyof the LO signal generated by the LO 250 may be anywhere with respect tothe RF bands of the multi-band RX and TX signals. FIG. 3 illustrates amulti-band RF RX signal as a signal having RX signal components 302,304, and 306. FIG. 3 illustrates a multi-band RF TX signal as a signalhaving TX signal components 312, 314, and 316. FIG. 3 furtherillustrates the LO signal 350.

The desired bands of the multi-band RX and TX signals shown in FIG. 3are 3GPP bands 1, 3 and 7. Namely, the RX signal component 302illustrates a signal in the uplink (i.e., the base station receives andthe user equipment transmits) operating band 3 (Rx B3), while the TXsignal component 312 illustrates a signal in the downlink (i.e., thebase station transmits and the user equipment receives) operating band 3(Tx B3); the RX signal component 304 illustrates a signal in the uplinkoperating band 1 (Rx B1), while the TX signal component 314 illustratesa signal in the downlink operating band 1 (Tx B1); and the RX signalcomponent 306 illustrates a signal in the uplink operating band 7 (RxB7), while the TX signal component 316 illustrates a signal in thedownlink operating band 7 (Tx B7). As can be seen from FIG. 3, orderived from the list of 3GPP bands, for the example shown in FIG. 3,the span of frequencies from the bottom of the lowest band (i.e., fromthe bottom of Rx B3) to the top of the highest band (i.e., to the top ofTx B7) is 980 MHz, which, for this example is the minimum transceiverbandwidth that may be used for the transceiver 200, TR×BW. For theoperating bands as shown in FIG. 3, the LO signal 350 generated by theLO 250 may be selected to be placed at the frequency of 2.2 GHz.

In the example of FIG. 3, the transmitter (i.e., the TX path 230 of thetransceiver 200) may upconvert a wideband signal (i.e., the signal thatincludes signal components which, after the upconversion, will becomethe TX signal components 312, 314, and 316) of a 980 MHz span offrequencies centered on DC to the three bands (i.e., 3GPP bands 1, 3,and 7) as shown in FIG. 3 with the TX signal components 312, 314, and316, using a single LO 250 generating an oscillation signal 350 with thefrequency of 2.2 GHz. Similarly, the receiver (i.e., the RX path 210 ofthe transceiver 200) may downconvert a wideband RF RX signal (i.e., thesignal that includes the RX signal components 302, 304, and 306) to a980 MHz span centered on DC.

For the example shown in FIG. 3, the transceiver 200 may operate asfollows. The LO 250 generates the LO signal 350. The RX quadrature mixer220 mixes the LO signal 350 with the multi-band RF RX signal thatincludes the RX signal components 302, 304, and 306 (i.e., components inthree separate bands of RF RX frequencies) to generate a downconvertedRX signal (not shown in FIG. 3) which is then provided to the ADC 224for conversion to digital. The downconverted RX signal is also amulti-band signal, i.e., it also includes signal components in threeseparate bands, but each of the signal components 302, 304, 306 areshifted down by the frequency LO, so that the downconverted RX signal isa signal of bandwidth TR×BW centered at DC (i.e., the downconverted RXsignal is a signal ranging from −490 MHz, which is −TR×BW/2 for theexample of FIG. 3, to 490 MHz, which is TR×BW/2 for the example of FIG.3). The TX quadrature mixer 240 mixes the same LO signal 350 with a TXsignal (not shown in FIG. 3) to generate an upconverted multi-band RF TXsignal that includes the TX signal components 312, 314, and 316 (i.e.,components in three separate bands of RF TX frequencies), whichupconverted TX signal is then provided to the antenna 202 for thetransmission. Similar to the upconverted TX signal shown in FIG. 3 withthe signal components 312, 314, and 316, the TX signal prior toupconversion (i.e., the signal which is not shown in FIG. 3) is also amulti-band signal, i.e., it also includes signal components in threeseparate bands, but the TX signal prior to upconversion is a signal ofbandwidth TR×BW centered at DC (i.e., the TX signal prior to conversionis a signal ranging from −490 MHz to 490 MHz for the example of FIG. 3).The TX quadrature mixer 240 shifts each of the signal components of theTX signal prior to conversion up by the frequency LO to generate theupconverted RF TX signal with the signal components 312, 314, and 316 asshown in FIG. 3. Because in the example of FIG. 3 the LO signal 350 doesnot overlap or is included in any of the RF bands, the downconverted RXsignal components and TX signal components prior to the upconversion arelow-IF signals.

In general, the TR×BW may be a fraction of the LO signal frequency. Forthe example of FIG. 3, the TR×BW is 980 MHz and the LO signal frequencyis 2.2 GHz. In other examples, when the LO signal is around 1 GHz, theTR×BW may be +/−250 MHz; when the LO signal is around 2 GHz, the TR×BWmay be +/−500 MHz; or when the LO signal is around 100 GHz, the TR×BWmay be +1-25 GHz. Thus, for the LO 250 configured to generate anoscillation signal with a frequency LO, the lowest edge of the usablebandwidth of the transceiver (for the example of FIG. 3, the bottom ofthe lowest band, Rx B3) may be about LO-LO/4, while the highest edge ofthe usable bandwidth of the transceiver (for the example of FIG. 3, thetop of the highest band, Tx B7) may be about LO+LO/4. For example, insome implementations, the difference between the top of the highest bandof RF frequencies for which the FDD receiver 200 is designed (for theexample of FIG. 3, the top of the highest band, Tx B7) and the LOfrequency may be less than about 120 MHz, while the difference betweenthe LO frequency and the bottom of the lowest band of RF frequencies forwhich the FDD receiver 200 is designed (for the example of FIG. 3, thebottom of the lowest band, Rx B3) and may be less than about 160 MHz. Ingeneral, these values may change depending on what the LO frequency is,so that each of 1) the difference between the top of the highest band ofRF frequencies for which the FDD receiver 200 is designed and the LOfrequency, and 2) the difference between the LO frequency and the bottomof the lowest band of RF frequencies for which the FDD receiver 200 isdesigned, may be less than about LO/4. It should be noted that thefrequencies described with reference to FIG. 3, as well as withreference to FIGS. 4-6 provide examples only. For example, in otherembodiments, TR×BW may be a larger fraction of the LO frequency thanabout LO/4.

FIG. 4 provides a graph 400, illustrating a different scenario. Inparticular, FIG. 4 illustrates that the transceiver 200 may need to bedesigned to handle a multi-band RF RX signal having signal components302 and 304 and to handle a multi-band RF TX signal having signalcomponents 312 and 314 as shown in FIG. 3 and described above (i.e., thesignal components of 3GPP bands 3 and 1, respectively). Thus, there areless RF bands in the scenario of FIG. 4, compared to the scenario ofFIG. 3, and the transceiver bandwidth TR×BW and the LO signal frequencyLO may be correspondingly reduced. FIG. 4 illustrates a scenario inwhich the LO 250 may be configured to generate a LO signal 450 which, asshown in FIG. 4, may be within one of the RF frequency bands ofinterest, namely—within the RF band of the RX signal component 304. Ascan be seen from FIG. 4, or derived from the list of 3GPP bands, for theexample shown in FIG. 4, the span of frequencies from the bottom of thelowest band (i.e., from the bottom of Rx B3) to the top of the highestband (i.e., to the top of Tx B1) is 460 MHz, which, for this example isthe minimum transceiver bandwidth that may be used for the transceiver200, TR×BW. For the operating bands as shown in FIG. 4, the LO signal450 generated by the LO 250 may be selected to be centered at thefrequency of about 1.95 GHz.

The general design principles described above with reference to FIG. 3are also applicable to FIG. 4. Namely, the TR×BW (460 MHz in the exampleof FIG. 4) is a fraction of the LO (1.95 GHz in the example of FIG. 4),and each of 1) the difference between the top of the highest band of RFfrequencies for which the FDD receiver 200 is designed (for the exampleof FIG. 4, the top of the highest band, Tx B1) and the LO frequency (thefrequency of the LO signal 450, which is 1.95 GHz in the example of FIG.4), and 2) the difference between the LO frequency and the bottom of thelowest band of RF frequencies for which the FDD receiver 200 is designed(for the example of FIG. 4, the bottom of the lowest band, Rx B3), maybe less than about LO/4 (i.e., less than about 487 MHz).

For the example shown in FIG. 4, the transceiver 200 may operate asfollows. The LO 250 generates the LO signal 450. The RX quadrature mixer220 mixes the LO signal 450 with the multi-band RF RX signal thatincludes the RX signal components 302 and 304 (i.e., components in twoseparate bands of RF RX frequencies) to generate a downconverted RXsignal (not shown in FIG. 4) which is then provided to the ADC 224 forconversion to digital. The downconverted RX signal is also a multi-bandsignal, i.e., it also includes signal components in two separate bands,but each of the signal components 302 and 304 are shifted down by thecenter frequency LO signal 450, so that the downconverted RX signal is asignal of bandwidth TR×BW centered at DC (i.e., the downconverted RXsignal is a signal ranging from −230 MHz, which is −TR×BW/2 for theexample of FIG. 4, to 230 MHz, which is TR×BW/2 for the example of FIG.4). The TX quadrature mixer 240 mixes the same LO signal 450 with a TXsignal (not shown in FIG. 4) to generate an upconverted multi-band RF TXsignal that includes the TX signal components 312 and 314 (i.e.,components in two separate bands of RF TX frequencies), whichupconverted TX signal is then provided to the antenna 202 for thetransmission. Similar to the upconverted TX signal shown in FIG. 4 withthe signal components 312 and 314, the TX signal prior to upconversion(i.e., the signal which is not shown in FIG. 4) is also a multi-bandsignal, i.e., it also includes signal components in two separate bands,but the TX signal prior to upconversion is a signal of bandwidth TR×BWcentered at DC (i.e., the TX signal prior to conversion is a signalranging from −230 MHz to 230 MHz for the example of FIG. 4). The TXquadrature mixer 240 shifts each of the signal components of the TXsignal prior to conversion up by the center frequency of the LO signal450 to generate the upconverted RF TX signal with the signal components312 and 314 as shown in FIG. 4. In contrast to the scenario of FIG. 3,because in the example of FIG. 4 the LO signal 450 does overlap withinone of the RF bands, namely, the RX band Rx B1, the downconverted RXsignal component of that band is a baseband signal (i.e., downconversionof that signal component with the LO signal 450 is a zero-IFconversion). The other RF signal components (i.e., the ones for whichthe LO signal 450 does not overlap or is included in the RF bands of)are low-IF signals as a result of their respective down- or upconversionusing the LO signal 450.

FIG. 5 provides a graph 500, illustrates yet another different scenario.In particular, FIG. 5 illustrates that the transceiver 200 may need tobe designed to handle a multi-band RF RX signal having signal components302 and 304 and to handle a multi-band RF TX signal having signalcomponents 312 and 314 as shown in FIG. 4 and described above (i.e., thesignal components of 3GPP bands 3 and 1, respectively). In contrast toFIG. 4, FIG. 5 illustrates a scenario in which the LO 250 may beconfigured to generate a LO signal 550 which, as shown in FIG. 5, may bewithin one of the RF frequency bands of interest, namely—within the RFband of the TX signal component 312. As can be seen from FIG. 5, orderived from the list of 3GPP bands, for the example shown in FIG. 5,the span of frequencies from the bottom of the lowest band (i.e., fromthe bottom of Rx B3) to the top of the highest band (i.e., to the top ofTx B1) is 460 MHz, which, for this example is the minimum transceiverbandwidth that may be used for the transceiver 200, TR×BW. For theoperating bands as shown in FIG. 5, the LO signal 550 generated by theLO 250 may be selected to be centered at the frequency of about 1.87GHz.

The general design principles described above with reference to FIGS. 3and 4 are also applicable to FIG. 5. Namely, the TR×BW (460 MHz in theexample of FIG. 5) may be a fraction of the LO (1.87 GHz in the exampleof FIG. 5), and each of 1) the difference between the top of the highestband of RF frequencies for which the FDD receiver 200 is designed (forthe example of FIG. 5, the top of the highest band, Tx B1) and the LOfrequency (the frequency of the LO signal 550, which is 1.87 GHz in theexample of FIG. 5), and 2) the difference between the LO frequency andthe bottom of the lowest band of RF frequencies for which the FDDreceiver 200 is designed (for the example of FIG. 5, the bottom of thelowest band, Rx B3), may be less than about LO/4 (i.e., less than about467 MHz). It should be noted that FIG. 5 illustrates an example wherethe bandwidth of the receiver (R×BW) is not the same as the bandwidth ofthe transmitter (T×BW).

For the example shown in FIG. 5, the transceiver 200 may operate asfollows. The LO 250 generates the LO signal 550. The RX quadrature mixer220 mixes the LO signal 550 with the multi-band RF RX signal thatincludes the RX signal components 302 and 304 (i.e., components in twoseparate bands of RF RX frequencies) to generate a downconverted RXsignal (not shown in FIG. 5) which is then provided to the ADC 224 forconversion to digital. The downconverted RX signal is also a multi-bandsignal, i.e., it also includes signal components in two separate bands,but each of the signal components 302 and 304 are shifted down by thecenter frequency LO signal 550, so that the downconverted RX signal is asignal of bandwidth TR×BW centered at DC (i.e., the downconverted RXsignal is a signal ranging from −230 MHz, which is −TR×BW/2 for theexample of FIG. 5, to 230 MHz, which is TR×BW/2 for the example of FIG.5). The TX quadrature mixer 240 mixes the same LO signal 550 with a TXsignal (not shown in FIG. 5) to generate an upconverted multi-band RF TXsignal that includes the TX signal components 312 and 314 (i.e.,components in two separate bands of RF TX frequencies), whichupconverted TX signal is then provided to the antenna 202 for thetransmission. Similar to the upconverted TX signal shown in FIG. 5 withthe signal components 312 and 314, the TX signal prior to upconversion(i.e., the signal which is not shown in FIG. 5) is also a multi-bandsignal, i.e., it also includes signal components in two separate bands,but the TX signal prior to upconversion is a signal of bandwidth TR×BWcentered at DC (i.e., the TX signal prior to conversion is a signalranging from −230 MHz to 230 MHz for the example of FIG. 5). The TXquadrature mixer 240 shifts each of the signal components of the TXsignal prior to conversion up by the center frequency of the LO signal550 to generate the upconverted RF TX signal with the signal components312 and 314 as shown in FIG. 5. In contrast to the scenario of FIG. 3,because in the example of FIG. 5 the LO signal 550 does overlap withinone of the RF bands, namely, the TX band Tx B3, the downconverted TXsignal component of that band is a baseband signal (i.e., downconversionof that signal component with the LO signal 550 is a zero-IFconversion). The other RF signal components (i.e., the ones for whichthe LO signal 550 does not overlap or is included in the RF bands of)are low-IF signals as a result of their respective down- or upconversionusing the LO signal 550.

FIG. 6 provides a graph 600, illustrating a further scenario. Inparticular, FIG. 6 illustrates that the transceiver 200 may need to bedesigned to handle a multi-band RF RX signal having signal components602 and 604 and to handle a multi-band RF TX signal having signalcomponents 612 and 614. The signal components 602 and 612 may be,respectively, RX and TX bands of 3GPP band 66, which is the widest bandat 70 MHz, where 3GPP bands 4 and 10 are subsets of band 66. The signalcomponents 604 and 614 may be, respectively, RX and TX bands of 3GPPband 2. As can be seen from FIG. 6, or derived from the list of 3GPPbands, for the example shown in FIG. 6, the span of frequencies from thebottom of the lowest band (i.e., from the bottom of Rx B66) to the topof the highest band (i.e., to the top of Tx B66) is 510 MHz. This may betoo much, or too complex, to support with a single LO. Therefore, insuch a scenario, two LOs may be used. A first LO may generate anoscillation signal with a frequency LO1, as shown in FIG. 6, which maybe used to mix with the received RF signals at all four receivers of thescenario of FIG. 6 (i.e., the receivers receiving RF signals in 3GPPbands 2 and 66) and to mix the transmitted TX signals at two of the fourtransmitters of this scenario (i.e., the transmitters transmitting RFsignals in 3GPP band 2), and a second LO may generate an oscillationsignal with a frequency LO2, shown in FIG. 6, which may be used to mixthe transmitted TX signals at the other two of the four transmitters ofthis scenario (i.e., the transmitters transmitting RF signals in 3GPPband 66. Thus, in the scenario of FIG. 6, the band 66 transmitter worksas in normal zero-IF mode and uses one of the local oscillators, namelythe one generating the LO signal LO2. Receivers in bands 2 and 66 andtransmitters of the band 2 share the other local oscillator (LO1).

The chip configuration for the scenario of FIG. 6 is shown as amulti-band FDD RF transceiver 700 shown in FIG. 7. The transceiver 700includes four RF transceivers, the approximate outlines of which areshown with the dashed outlines and labels TR1, TR2, TR3, and TR 4. Eachof the transceivers TR1, TR2, TR3, and TR 4 may be the RF transceiver200 as described above (which can be seen in FIG. 7 showing analogouscomponents to those shown in FIG. 2), except that the configuration andsharing of the signals of the LO 250 may be different. Namely, as shownin FIG. 7, a first LO (LO1) may be used in quadrature mixers of all fourreceivers (i.e., the receivers of the RF transceivers TR1, TR2, TR3, andTR 4) and in quadrature mixers of two of the four transmitters (as shownin FIG. 7, in the transmitters of the RF transceivers TR1 and TR2),while a second LO (LO2) may be used in quadrature mixers of theremaining two of the four transmitters (i.e., in the transmitters of theRF transceivers TR3 and TR4).

Example Data Processing System

FIG. 8 provides a block diagram illustrating an example data processingsystem 800 that may be configured to implement at least portions of thecontroller 270 which may be used to control operation of the multi-bandFDD transceiver, e.g., the transceiver 200 or 700, according to someembodiments of the present disclosure.

As shown in FIG. 8, the data processing system 800 may include at leastone processor 802, e.g. a hardware processor 802, coupled to memoryelements 804 through a system bus 806. As such, the data processingsystem may store program code within memory elements 804. Further, theprocessor 802 may execute the program code accessed from the memoryelements 804 via a system bus 806. In one aspect, the data processingsystem may be implemented as a computer that is suitable for storingand/or executing program code. It should be appreciated, however, thatthe data processing system 800 may be implemented in the form of anysystem including a processor and a memory that is capable of performingthe functions described within this disclosure.

In some embodiments, the processor 802 can execute software or analgorithm to perform the activities as discussed in this specification,in particular activities related to operation of one or more FDDtransceivers using one or more LOs shared among multiple RX and/or TXbands. The processor 802 may include any combination of hardware,software, or firmware providing programmable logic, including by way ofnon-limiting example a microprocessor, a digital signal processor (DSP),a field-programmable gate array (FPGA), a programmable logic array(PLA), an application specific IC (ASIC), or a virtual machineprocessor. The processor 802 may be communicatively coupled to thememory element 804, for example in a direct-memory access (DMA)configuration, so that the processor 802 may read from or write to thememory elements 804.

In general, the memory elements 804 may include any suitable volatile ornon-volatile memory technology, including double data rate (DDR) randomaccess memory (RAM), synchronous RAM (SRAM), dynamic RAM (DRAM), flash,read-only memory (ROM), optical media, virtual memory regions, magneticor tape memory, or any other suitable technology. Unless specifiedotherwise, any of the memory elements discussed herein should beconstrued as being encompassed within the broad term “memory.” Theinformation being measured, processed, tracked or sent to or from any ofthe components of the data processing system 800 could be provided inany database, register, control list, cache, or storage structure, allof which can be referenced at any suitable timeframe. Any such storageoptions may be included within the broad term “memory” as used herein.Similarly, any of the potential processing elements, modules, andmachines described herein should be construed as being encompassedwithin the broad term “processor.” Each of the elements shown in thepresent figures, e.g. the ADCs 224, the DACs 244, or otherelements/components shown in FIG. 2 or 7, can also include suitableinterfaces for receiving, transmitting, and/or otherwise communicatingdata or information in a network environment so that they cancommunicate with, e.g., the data processing system 800 implementing thecontroller 270.

In certain example implementations, mechanisms for operation of one ormore FDD transceivers using one or more LOs shared among multiple RXand/or TX bands as outlined herein may be implemented by logic encodedin one or more tangible media, which may be inclusive of non-transitorymedia, e.g., embedded logic provided in an ASIC, in DSP instructions,software (potentially inclusive of object code and source code) to beexecuted by a processor, or other similar machine, etc. In some of theseinstances, memory elements, such as e.g. the memory elements 804 shownin FIG. 8, can store data or information used for the operationsdescribed herein. This includes the memory elements being able to storesoftware, logic, code, or processor instructions that are executed tocarry out the activities described herein. A processor can execute anytype of instructions associated with the data or information to achievethe operations detailed herein. In one example, the processors, such ase.g. the processor 802 shown in FIG. 8, could transform an element or anarticle (e.g., data) from one state or thing to another state or thing.In another example, the activities outlined herein may be implementedwith fixed logic or programmable logic (e.g., software/computerinstructions executed by a processor) and the elements identified hereincould be some type of a programmable processor, programmable digitallogic (e.g., an FPGA, a DSP, an erasable programmable read-only memory(EPROM), an electrically erasable programmable read-only memory(EEPROM)) or an ASIC that includes digital logic, software, code,electronic instructions, or any suitable combination thereof.

The memory elements 804 may include one or more physical memory devicessuch as, for example, local memory 808 and one or more bulk storagedevices 810. The local memory may refer to RAM or other non-persistentmemory device(s) generally used during actual execution of the programcode. A bulk storage device may be implemented as a hard drive or otherpersistent data storage device. The processing system 800 may alsoinclude one or more cache memories (not shown) that provide temporarystorage of at least some program code in order to reduce the number oftimes program code must be retrieved from the bulk storage device 810during execution.

As shown in FIG. 8, the memory elements 804 may store an application818. In various embodiments, the application 818 may be stored in thelocal memory 808, the one or more bulk storage devices 810, or apartfrom the local memory and the bulk storage devices. It should beappreciated that the data processing system 800 may further execute anoperating system (not shown in FIG. 8) that can facilitate execution ofthe application 818. The application 818, being implemented in the formof executable program code, can be executed by the data processingsystem 800, e.g., by the processor 802. Responsive to executing theapplication, the data processing system 800 may be configured to performone or more operations or method steps described herein.

Input/output (I/O) devices depicted as an input device 812 and an outputdevice 814, optionally, can be coupled to the data processing system.Examples of input devices may include, but are not limited to, akeyboard, a pointing device such as a mouse, or the like. Examples ofoutput devices may include, but are not limited to, a monitor or adisplay, speakers, or the like. In some embodiments, the output device814 may be any type of screen display, such as plasma display, liquidcrystal display (LCD), organic light emitting diode (OLED) display,electroluminescent (EL) display, or any other indicator, such as a dial,barometer, or LEDs. In some implementations, the system may include adriver (not shown) for the output device 814. Input and/or outputdevices 812, 814 may be coupled to the data processing system eitherdirectly or through intervening I/O controllers.

In an embodiment, the input and the output devices may be implemented asa combined input/output device (illustrated in FIG. 8 with a dashed linesurrounding the input device 812 and the output device 814). An exampleof such a combined device is a touch sensitive display, also sometimesreferred to as a “touch screen display” or simply “touch screen”. Insuch an embodiment, input to the device may be provided by a movement ofa physical object, such as e.g. a stylus or a finger of a user, on ornear the touch screen display.

A network adapter 816 may also, optionally, be coupled to the dataprocessing system to enable it to become coupled to other systems,computer systems, remote network devices, and/or remote storage devicesthrough intervening private or public networks. The network adapter maycomprise a data receiver for receiving data that is transmitted by saidsystems, devices and/or networks to the data processing system 800, anda data transmitter for transmitting data from the data processing system800 to said systems, devices and/or networks. Modems, cable modems, andEthernet cards are examples of different types of network adapter thatmay be used with the data processing system 800.

Select Examples

Example 1 provides a multi-band FDD transceiver system that includes aLO, a receive (RX) quadrature mixer (i.e., a mixer in the RX path thatis configured to perform quadrature mixing of signals, the RX quadraturemixer also commonly referred to as a downconverter), and a transmit (TX)quadrature mixer (i.e., a mixer in the TX path, also commonly referredto as an upconverter). The LO is configured to provide a LO signal. TheRX quadrature mixer is configured to mix the LO signal with a receivedRF signal to generate a downconverted RX signal, where the received RFsignal includes a first received signal component in a first band of RFreceiver frequencies and a second received signal component in a secondband of RF receiver frequencies, the second band of receiver frequenciesbeing separate from (i.e., being non-overlapping and non-continuouswith) the first band of receiver frequencies. The TX quadrature mixer isconfigured to mix the LO signal with a TX signal to generate anupconverted RF TX signal, where the upconverted TX signal includes afirst upconverted TX signal component in a first band of transmitterfrequencies and a second upconverted TX signal component in a secondband of transmitter frequencies, the second band of transmitterfrequencies being separate from (i.e., being non-overlapping andnon-continuous with) each one of the first band of transmitterfrequencies, the first band of receiver frequencies, and the second bandof receiver frequencies.

Example 2 provides the multi-band FDD transceiver system according toexample 1, where a center frequency of the LO signal is within the firstband of receiver frequencies (i.e., the first receiver signal componentis downconverted to baseband, i.e., a zero-IF conversion, as a result ofbeing mixed with the LO signal).

Example 3 provides the multi-band FDD transceiver system according toexample 1, where a center frequency of the LO signal is within the firstband of transmitter frequencies (i.e., the first upconverted TX signalcomponent prior to the upconversion is a baseband signal component).

Example 4 provides the multi-band FDD transceiver system according toany one of the preceding examples, where the downconverted RX signalincludes an in-phase RX signal component and a quadrature RX signalcomponent, and the RX quadrature mixer includes a first RX path mixerand a second RX path mixer, where the first RX path mixer is configuredto generate the in-phase RX signal component based on the received RFsignal and an in-phase component of the LO signal (i.e., cos(LO)), andthe second RX path mixer is configured to generate the quadrature RXsignal component based on the received RF signal and a quadraturecomponent of the LO signal (i.e., sin(LO), or a component that is offsetin phase from the in-phase component of the LO signal by 90 degrees).

Example 5 provides the multi-band FDD transceiver system according toexample 4, further including a first ADC, configured to convert thein-phase RX signal component to a digital in-phase RX signal component,and also including a second ADC, configured to convert the quadrature RXsignal component to a digital quadrature RX signal component.

Example 6 provides the multi-band FDD transceiver system according toexample 5, further including a first band-pass filter (BPF), having aninput coupled to an output of the first RX path mixer, and having anoutput coupled to an input of the first ADC (i.e., configured to filteran output of the first RX path mixer to generate a filtered in-phase RXsignal component for conversion by the first ADC); and a second BPF,having an input coupled to an output of the second RX path mixer, andhaving an output coupled to an input of the second ADC (i.e., configuredto filter an output of the second RX path mixer to generate a filteredin-phase RX signal component for conversion by the second ADC).

Example 7 provides the multi-band FDD transceiver system according toany one of the preceding examples, where the upconverted TX signalincludes an in-phase upconverted TX signal component and a quadratureupconverted TX signal component, and the TX quadrature mixer includes afirst TX path mixer and a second TX path mixer, where the first TX pathmixer is configured to generate the in-phase upconverted TX signalcomponent based on the TX signal and an in-phase component of the LOsignal (i.e., cos(LO)), and the second TX path mixer is configured togenerate the quadrature upconverted TX signal component based on the TXsignal and a quadrature component of the LO signal (i.e., sin(LO)).

Example 8 provides the multi-band FDD transceiver system according toexample 7, further including a first DAC, configured to convert adigital in-phase TX signal component to an analog in-phase TX signalcomponent, where the first TX path mixer is configured to generate thein-phase upconverted TX signal component based on the analog in-phase TXsignal component; and a second DAC, configured to convert a digitalquadrature TX signal component to an analog quadrature TX signalcomponent, where the second TX path mixer is configured to generate thequadrature upconverted TX signal component based on the analogquadrature TX signal component.

Example 9 provides the multi-band FDD transceiver system according toexample 8, further including a first BPF, having an input coupled to anoutput of the first DAC, and having an output coupled to an input of thefirst TX path mixer (i.e., configured to filter an output of the firstDAC prior to providing it for mixing at the first TX path mixer); and asecond BPF, having an input coupled to an output of the second DAC, andhaving an output coupled to an input of the second TX path mixer (i.e.,configured to filter an output of the second DAC prior to providing itfor mixing at the second TX path mixer).

Example 10 provides the multi-band FDD transceiver system according toany one of the preceding examples, where the RX quadrature mixer mixingthe LO signal with the received RF signal includes the RX quadraturemixer performing a quadrature downconversion to generate thedownconverted RX signal, and the TX quadrature mixer mixing the LOsignal with the TX signal includes the TX quadrature mixer performing aquadrature upconversion to generate the upconverted TX signal.

Example 11 provides the multi-band FDD transceiver system according toany one of the preceding examples, where a difference between afrequency of the LO signal and a smallest frequency of the received RFsignal (e.g., the smallest frequency of the first band of receiverfrequencies and the second band of receiver frequencies) is less than160 megahertz.

Example 12 provides the multi-band FDD transceiver system according toany one of the preceding examples, where a difference between afrequency of the LO signal and a largest frequency of the upconverted TXsignal (e.g., the largest frequency of the first band of transceiverfrequencies and the second band of transceiver frequencies) is less than120 megahertz.

Example 13 provides the multi-band FDD transceiver system according toany one of examples 1-12, further including a further LO, configured toprovide a further LO signal; a further TX path mixer, configured to mixthe further LO signal with a further TX signal to generate a furthermixed TX signal.

Example 14 provides the multi-band FDD transceiver system according toany one of examples 1-12, further including a further LO, configured toprovide a further LO signal; a further RX path mixer, configured to mixthe further LO signal with a further RX signal to generate a furthermixed RX signal.

Example 15 provides the multi-band FDD transceiver system according toany one of the preceding examples, further including a LNA, configuredto amplify the received RF signal prior to the RX path mixer mixing theLO signal with the received RF signal, and/or a power amplifier,configured to amplify the upconverted TX signal.

Example 16 provides a multi-band FDD transceiver that includes a firstLO, configured to provide a first LO signal; a second LO, configured toprovide a second LO signal; a first receive (RX) path mixer, configuredto mix the first LO signal with a first RX signal to generate a firstmixed RX signal; a second RX path mixer, configured to mix the first LOsignal with a second RX signal to generate a second mixed RX signal; afirst transmit (TX) path mixer, configured to mix the first LO signalwith a first TX signal to generate a first mixed TX signal; and a secondTX path mixer, configured to mix the second LO signal with a second TXsignal to generate a second mixed TX signal.

Example 17 provides the multi-band FDD transceiver system according toexample 16, where each of the first RX signal, the second RX signal, thefirst TX signal, and the second TX signal is in a respective differentband of frequencies.

Example 18 provides the multi-band FDD transceiver system according toexamples 16 or 17, further including: a third RX path mixer, configuredto mix the first LO signal with a third RX signal to generate a thirdmixed RX signal; and a third TX path mixer, configured to mix the firstLO signal with a third TX signal to generate a third mixed TX signal.

Example 19 provides the multi-band FDD transceiver system according toexample 18, further including: a fourth RX path mixer, configured to mixthe first LO signal with a fourth RX signal to generate a fourth mixedRX signal; and a fourth TX path mixer, configured to mix the second LOsignal with a fourth TX signal to generate a fourth mixed TX signal.

Example 20 provides a non-transitory computer-readable storage mediumincluding instructions for execution which, when executed by aprocessor, are operable to perform operations including: controllingthat a LO generates a LO signal; controlling that a receive (RX) pathmixer mixes the LO signal with a received RF signal to generate adownconverted RX signal, where the received RF signal includes a firstreceived signal component in a first band of RF receiver frequencies anda second received signal component in a second band of RF receiverfrequencies, the second band of receiver frequencies being separate from(i.e., being non-overlapping and non-continuous with) the first band ofreceiver frequencies; and controlling that a transmit (TX) path mixermixes the LO signal with a TX signal to generate an upconverted RF TXsignal, where the upconverted TX signal includes a first upconverted TXsignal component in a first band of transmitter frequencies and a secondupconverted TX signal component in a second band of transmitterfrequencies, the second band of transmitter frequencies being separatefrom (i.e., being non-overlapping and non-continuous with) each one ofthe first band of transmitter frequencies, the first band of receiverfrequencies, and the second band of receiver frequencies.

In further examples, the non-transitory computer-readable storage mediumaccording to example 20 may further include instructions operable toperform operations performed by any parts of the multi-band FDDtransceiver system in accordance with any one of the preceding examples.

Variations and Implementations

While embodiments of the present disclosure were described above withreferences to exemplary implementations as shown in FIGS. 1-8, a personskilled in the art will realize that the various teachings describedabove are applicable to a large variety of other implementations. Forexample, the same principles may be applied with two or more LOs eachsupporting receivers and transmitters in groups of bands. In someembodiments, the LOs may be derived from a single frequency source thatis followed by different dividers.

In certain contexts, the features discussed herein can be applicable toautomotive systems, safety-critical industrial applications, medicalsystems, scientific instrumentation, wireless and wired communications,radio, radar, industrial process control, audio and video equipment,current sensing, instrumentation (which can be highly precise), andother digital-processing-based systems.

Moreover, certain embodiments discussed above can be provisioned indigital signal processing technologies for medical imaging, patientmonitoring, medical instrumentation, and home healthcare. This couldinclude pulmonary monitors, accelerometers, heart rate monitors,pacemakers, etc. Other applications can involve automotive technologiesfor safety systems (e.g., stability control systems, driver assistancesystems, braking systems, infotainment and interior applications of anykind).

In yet other example scenarios, the teachings of the present disclosurecan be applicable in the industrial markets that include process controlsystems that help drive productivity, energy efficiency, andreliability. In consumer applications, the teachings of the signalprocessing circuits discussed above can be used for image processing,auto focus, and image stabilization (e.g., for digital still cameras,camcorders, etc.). Other consumer applications can include audio andvideo processors for home theater systems, DVD recorders, andhigh-definition televisions.

In the discussions of the embodiments above, components of a system,such as e.g. clocks, multiplexers, buffers, and/or other components canreadily be replaced, substituted, or otherwise modified in order toaccommodate particular circuitry needs. Moreover, it should be notedthat the use of complementary electronic devices, hardware, software,etc. offer an equally viable option for implementing the teachings ofthe present disclosure related to virtual dithering.

Parts of various systems for sharing one or more LOs shared amongmultiple RX and/or TX bands in a multi-band FDD transceiver as proposedherein can include electronic circuitry to perform the functionsdescribed herein. In some cases, one or more parts of the system can beprovided by a processor specially configured for carrying out thefunctions described herein. For instance, the processor may include oneor more application specific components, or may include programmablelogic gates which are configured to carry out the functions describeherein. The circuitry can operate in analog domain, digital domain, orin a mixed-signal domain. In some instances, the processor may beconfigured to carrying out the functions described herein by executingone or more instructions stored on a non-transitory computer-readablestorage medium.

In one example embodiment, any number of electrical circuits of thepresent figures may be implemented on a board of an associatedelectronic device. The board can be a general circuit board that canhold various components of the internal electronic system of theelectronic device and, further, provide connectors for otherperipherals. More specifically, the board can provide the electricalconnections by which the other components of the system can communicateelectrically. Any suitable processors (inclusive of DSPs,microprocessors, supporting chipsets, etc.), computer-readablenon-transitory memory elements, etc. can be suitably coupled to theboard based on particular configuration needs, processing demands,computer designs, etc. Other components such as external storage,additional sensors, controllers for audio/video display, and peripheraldevices may be attached to the board as plug-in cards, via cables, orintegrated into the board itself. In various embodiments, thefunctionalities described herein may be implemented in emulation form assoftware or firmware running within one or more configurable (e.g.,programmable) elements arranged in a structure that supports thesefunctions. The software or firmware providing the emulation may beprovided on non-transitory computer-readable storage medium comprisinginstructions to allow a processor to carry out those functionalities.

In another example embodiment, the electrical circuits of the presentfigures may be implemented as stand-alone modules (e.g., a device withassociated components and circuitry configured to perform a specificapplication or function) or implemented as plug-in modules intoapplication specific hardware of electronic devices. Note thatparticular embodiments of the present disclosure may be readily includedin a system on chip (SOC) package, either in part, or in whole. An SOCrepresents an IC that integrates components of a computer or otherelectronic system into a single chip. It may contain digital, analog,mixed-signal, and often RF functions: all of which may be provided on asingle chip substrate. Other embodiments may include a multi-chip-module(MCM), with a plurality of separate ICs located within a singleelectronic package and configured to interact closely with each otherthrough the electronic package.

It is also imperative to note that all of the specifications,dimensions, and relationships outlined herein (e.g., the number ofcomponents of the transceivers shown in FIGS. 2 and 7, and/or the numberand values of RF bands shown in FIGS. 3-6, etc.) have only been offeredfor purposes of example and teaching only. Such information may bevaried considerably without departing from the spirit of the presentdisclosure, or the scope of the appended claims. The specificationsapply only to one non-limiting example and, accordingly, they should beconstrued as such. In the foregoing description, example embodimentshave been described with reference to particular processor and/orcomponent arrangements. Various modifications and changes may be made tosuch embodiments without departing from the scope of the appendedclaims. The description and drawings are, accordingly, to be regarded inan illustrative rather than in a restrictive sense.

Note that with the numerous examples provided herein, interaction may bedescribed in terms of two, three, four, or more electrical components.However, this has been done for purposes of clarity and example only. Itshould be appreciated that the system can be consolidated in anysuitable manner. Along similar design alternatives, any of theillustrated components, modules, and elements of the present FIGS. maybe combined in various possible configurations, all of which are clearlywithin the broad scope of this Specification. In certain cases, it maybe easier to describe one or more of the functionalities of a given setof flows by only referencing a limited number of electrical elements. Itshould be appreciated that the electrical circuits of the presentfigures and its teachings are readily scalable and can accommodate alarge number of components, as well as more complicated/sophisticatedarrangements and configurations. Accordingly, the examples providedshould not limit the scope or inhibit the broad teachings of theelectrical circuits as potentially applied to a myriad of otherarchitectures.

Note that in this Specification, references to various features (e.g.,elements, structures, modules, components, steps, operations,characteristics, etc.) included in “one embodiment”, “exampleembodiment”, “an embodiment”, “another embodiment”, “some embodiments”,“various embodiments”, “other embodiments”, “alternative embodiment”,and the like are intended to mean that any such features are included inone or more embodiments of the present disclosure, but may or may notnecessarily be combined in the same embodiments.

It is also important to note that the functions related to operation ofone or more FDD transceivers using one or more LOs shared among multipleRX and/or TX bands as proposed herein illustrate only some of thepossible functions that may be executed by, or within, systemillustrated in the present figures. Some of these operations may bedeleted or removed where appropriate, or these operations may bemodified or changed considerably without departing from the scope of thepresent disclosure. In addition, the timing of these operations may bealtered considerably. The preceding operational flows have been offeredfor purposes of example and discussion. Substantial flexibility isprovided by embodiments described herein in that any suitablearrangements, chronologies, configurations, and timing mechanisms may beprovided without departing from the teachings of the present disclosure.

Note that all optional features of the apparatus described above mayalso be implemented with respect to the method or process describedherein and specifics in the examples may be used anywhere in one or moreembodiments.

Numerous other changes, substitutions, variations, alterations, andmodifications may be ascertained to one skilled in the art and it isintended that the present disclosure encompass all such changes,substitutions, variations, alterations, and modifications as fallingwithin the scope of the appended claims.

Although the claims are presented in single dependency format in thestyle used before the USPTO, it should be understood that any claim candepend on and be combined with any preceding claim of the same typeunless that is clearly technically infeasible.

1. A multi-band frequency division duplex (FDD) transceiver system,comprising: a local oscillator (LO), configured to provide a LO signal;a receive (RX) quadrature mixer, configured to mix the LO signal with areceived radio frequency (RF) signal to generate a downconverted RXsignal, where the received RF signal includes a first received signalcomponent in a first band of receiver frequencies and a second receivedsignal component in a second band of receiver frequencies, the secondband of receiver frequencies being separate from the first band ofreceiver frequencies; and a transmit (TX) quadrature mixer, configuredto mix the LO signal with a TX signal to generate an upconverted RF TXsignal, where the upconverted TX signal includes a first upconverted TXsignal component in a first band of transmitter frequencies and a secondupconverted TX signal component in a second band of transmitterfrequencies, the second band of transmitter frequencies being separatefrom each one of the first band of transmitter frequencies, the firstband of receiver frequencies, and the second band of receiverfrequencies.
 2. The multi-band FDD transceiver system according to claim1, wherein a frequency of the LO signal is within the first band ofreceiver frequencies.
 3. The multi-band FDD transceiver system accordingto claim 1, wherein a frequency of the LO signal is within the firstband of transmitter frequencies.
 4. The multi-band FDD transceiversystem according to claim 1, wherein: the downconverted RX signalincludes an in-phase RX signal component and a quadrature RX signalcomponent, and the RX quadrature mixer includes a first RX path mixerand a second RX path mixer, where the first RX path mixer is configuredto generate the in-phase RX signal component based on the received RFsignal and an in-phase component of the LO signal, and the second RXpath mixer is configured to generate the quadrature RX signal componentbased on the received RF signal and a quadrature component of the LOsignal.
 5. The multi-band FDD transceiver system according to claim 4,further comprising: a first analog-to-digital converter (ADC),configured to convert the in-phase RX signal component to a digitalin-phase RX signal component; and a second ADC, configured to convertthe quadrature RX signal component to a digital quadrature RX signalcomponent.
 6. The multi-band FDD transceiver system according to claim5, further comprising: a first filter, having an input coupled to anoutput of the first RX path mixer, and having an output coupled to aninput of the first ADC; and a second filter, having an input coupled toan output of the second RX path mixer, and having an output coupled toan input of the second ADC.
 7. The multi-band FDD transceiver systemaccording to claim 1, wherein: the upconverted TX signal includes anin-phase upconverted TX signal component and a quadrature upconverted TXsignal component, and the TX quadrature mixer includes a first TX pathmixer and a second TX path mixer, where the first TX path mixer isconfigured to generate the in-phase upconverted TX signal componentbased on the TX signal and an in-phase component of the LO signal, andthe second TX path mixer is configured to generate the quadratureupconverted TX signal component based on the TX signal and a quadraturecomponent of the LO signal.
 8. The multi-band FDD transceiver systemaccording to claim 7, further comprising: a first digital-to-analogconverter (DAC), configured to convert a digital in-phase TX signalcomponent to an analog in-phase TX signal component, where the first TXpath mixer is configured to generate the in-phase upconverted TX signalcomponent based on the analog in-phase TX signal component; and a secondDAC, configured to convert a digital quadrature TX signal component toan analog quadrature TX signal component, where the second TX path mixeris configured to generate the quadrature upconverted TX signal componentbased on the analog quadrature TX signal component.
 9. The multi-bandFDD transceiver system according to claim 8, further comprising: a firstfilter, having an input coupled to an output of the first DAC, andhaving an output coupled to an input of the first TX path mixer; and asecond filter, having an input coupled to an output of the second DAC,and having an output coupled to an input of the second TX path mixer.10. The multi-band FDD transceiver system according to claim 1, wherein:the RX quadrature mixer mixing the LO signal with the received RF signalincludes the RX quadrature mixer performing a quadrature downconversionto generate the downconverted RX signal, and the TX quadrature mixermixing the LO signal with the TX signal includes the TX quadrature mixerperforming a quadrature upconversion to generate the upconverted TXsignal.
 11. The multi-band FDD transceiver system according to claim 1,wherein a difference between a frequency of the LO signal and a smallestfrequency of the received RF signal is less than 160 megahertz.
 12. Themulti-band FDD transceiver system according to claim 1, wherein adifference between a frequency of the LO signal and a largest frequencyof the upconverted TX signal is less than 120 megahertz.
 13. Themulti-band FDD transceiver system according to claim 1, furtherincluding: a further LO, configured to provide a further LO signal; afurther TX path mixer, configured to mix the further LO signal with afurther TX signal to generate a further mixed TX signal.
 14. Themulti-band FDD transceiver system according to claim 1, furtherincluding: a further LO, configured to provide a further LO signal; afurther RX path mixer, configured to mix the further LO signal with afurther RX signal to generate a further mixed RX signal.
 15. Themulti-band FDD transceiver system according to claim 1, furthercomprising: a low-noise amplifier (LNA), configured to amplify thereceived RF signal prior to the RX path mixer mixing the LO signal withthe received RF signal, and/or a power amplifier, configured to amplifythe upconverted TX signal.
 16. A multi-band frequency division duplex(FDD) transceiver, comprising: a first local oscillator (LO), configuredto provide a first LO signal; a second LO, configured to provide asecond LO signal; a first receive (RX) path mixer, configured to mix thefirst LO signal with a first RX signal to generate a first mixed RXsignal; a second RX path mixer, configured to mix the first LO signalwith a second RX signal to generate a second mixed RX signal; a firsttransmit (TX) path mixer, configured to mix the first LO signal with afirst TX signal to generate a first mixed TX signal; and a second TXpath mixer, configured to mix the second LO signal with a second TXsignal to generate a second mixed TX signal.
 17. The multi-band FDDtransceiver system according to claim 16, wherein each of the first RXsignal, the second RX signal, the first TX signal, and the second TXsignal is in a respective different band of frequencies.
 18. Themulti-band FDD transceiver system according to claim 16, furtherincluding: a third RX path mixer, configured to mix the first LO signalwith a third RX signal to generate a third mixed RX signal; and a thirdTX path mixer, configured to mix the first LO signal with a third TXsignal to generate a third mixed TX signal.
 19. The multi-band FDDtransceiver system according to claim 18, further including: a fourth RXpath mixer, configured to mix the first LO signal with a fourth RXsignal to generate a fourth mixed RX signal; and a fourth TX path mixer,configured to mix the second LO signal with a fourth TX signal togenerate a fourth mixed TX signal.
 20. A non-transitorycomputer-readable storage medium comprising instructions for executionwhich, when executed by a processor, are operable to perform operationscomprising: controlling that a local oscillator (LO) generates a LOsignal; controlling that a receive (RX) path mixer mixes the LO signalwith a received radio frequency (RF) signal to generate a downconvertedRX signal, where the received RF signal includes a first received signalcomponent in a first band of receiver frequencies and a second receivedsignal component in a second band of receiver frequencies, the secondband of receiver frequencies being separate from the first band ofreceiver frequencies; and controlling that a transmit (TX) path mixermixes the LO signal with a TX signal to generate an upconverted TXsignal, where the upconverted TX signal includes a first upconverted TXsignal component in a first band of transmitter frequencies and a secondupconverted TX signal component in a second band of transmitterfrequencies, the second band of transmitter frequencies being separatefrom each one of the first band of transmitter frequencies, the firstband of receiver frequencies, and the second band of receiverfrequencies.